1. Field of the Invention
The present invention relates to a medical winged needle assembly such as a PSV (Pediatric Scalp Vein) set, an AVF (Arteriovenous Fistula) set, etc., for dialysis, infusion, blood transfusion and the like. More specifically, it relates to improvements in a guarded medical winged needle assembly and relates to a guarded medical winged needle assembly that is improved in handling while maintaining the reliability and safety thereof.
2. Description of the Related Art
In recent years, with the spread of infectious diseases such as virus hepatitis, AIDS, etc., which are transmitted through a medical needle contaminated with blood or body fluid of a disease carrier, medical institutes have a problem of infections caused by accidental needlesticks of medical staff workers who work on blood transfusion, dialysis, etc. Further, there has been a possibility of a waste disposer being accidentally stuck with a needle to which contaminated blood adheres while he or she is at work.
To address this problem, there have been proposed some guarded medical winged needle assemblies that are capable of safely encasing a used needle. The present inventors have proposed an invention directed to a guarded winged needle assembly with a pair of wing-shaped stoppers disposed on both sides of its middle portion in JP-A-2001-327599 (P2001-327599A). In this invention, a used winged needle is encased in the above needle guard, and then both wings of the winged needle are folded upward, thereby the two wings intersect with, and are engaged with, the wing-shaped stoppers and the winged needle does not protrude from the needle cover.
In JP-A-2003-116996 (P2003-116996A), the present inventors have also proposed that a tube connected to the hub of the above guarded winged needle assembly be fixed into a groove formed in the backward portion of the needle cover for fixing the needle more securely. (U.S. Pat. No. 6,736,798 to the present assignee discloses an invention to the same effect.)
In the above-proposed winged needle assembly, however, the intersection and engagement of the two wings with the wing-shaped stoppers is complicated and needs a considerable skill. In particular, it has not been easy at all for a worker having large inexpert hands to perform the operations of folding the two wings of the winged needle assembly upward and further causing the above two wings to intersect and be engaged with the wing-shaped stopper of the needle cover.
Further, U.S. Pat. No. 5,931,815 to Liu discloses a multifunctional safety infusion set with injection needle retractable in a wing-equipped sheath. Specifically, as shown in FIGS. 3 to 5 attached to the above U.S. patent, the safety infusion set has an upper engaging section 11 with a spiral groove and a lower engaging section 12 with a latch groove formed around the outer periphery of a tube body 10 positioned next to the bottom end of a needle seat 31. When a needle 32 is enclosed in the wing-equipped sheath 4, the lower engaging section 12 slides over a backward end portion (connecting section 411) of the wing-equipped sheath 4 to an outside of the sheath, and the upper engaging section 11 is engaged or screw-fixed with the backward end portion 411 of the wing-equipped sheath 4.
In the invention of the above '815 U.S. patent to Liu, when the needle 32 is to be enclosed in the wing-equipped sheath 4, it is required to perform a double-step operation of causing the lower engaging section 12 to go over the backward end of the wing-equipped sheath 4 first and then causing the upper engaging section 11 to be screw-engaged with the backward portion of the wing-equipped sheath 4. This double-step operation is complicated and troublesome.
Further, U.S. Pat. No. 6,200,294 to Liu discloses syringe with a safety slide sleeve that can receive and hide an injection needle therein. Specifically, the syringe has a tube body 10 positioned next to the backward end of a needle holder 31 and a plurality of axially downward extending and downward tapered guiding ribs 12 formed on the tube body as shown in FIGS. 1 to 5 attached to the above U.S. patent. When an injection needle 3 is received in the safety slide sleeve 4, the guiding ribs 12 slide over an inward extending latching flange 411 on the backward end (bottom portion) of the safety slide sleeve 4 and become to be engaged with the backward wall surface of the safety slide sleeve 4.
The syringe according to the invention of the above U.S. patent to Liu does not have any wing at all, and when the needle is kept in the above safety slide sleeve, the syringe does not permit the operation of fluid infusion, or the like. Further, when the injection needle 3 is received in the safety slide sleeve 4, it is required to cause the plurality of guiding ribs to slide over the backward end of the safety slide sleeve 4, and such an operation hence needs a considerably strong force. The syringe of the above U.S. patent involves a difficulty in operation.
U.S. Pat. No. 5,219,339 to Saito (note: JP-A-H3-158171 as Japanese laid-open publication of family patent) discloses a disposable injection needle integrated with a cap, comprising a cannula N, a body 1 for holding the cannula, the body having a broad columnar body 6, slants 4 and several necks, and a cap 10 having a flange for engagement with the necks, the cap 10 being for engagement with the body 1.
The invention of the above U.S. patent to Saito is not at all directed to any winged needle set. Further, when the cannula N is encased in the needle cap 10, the broad columnar body 6 and the slants 4 are required to go over the backward portion of the needle cap 10, causing such an operation troublesome.